a. Field of the Invention
This disclosure relates to a fluid pump for a linear actuator. In particular, the instant disclosure relates to a fluid pump providing improvements in operating efficiencies, flexibility of use and packaging.
b. Background Art
In a fluid controlled linear actuator, a double acting piston is disposed within a fluid chamber and connected to an actuator rod extending from the fluid chamber. Fluid is delivered to and removed from the fluid chamber on opposite sides of the piston in order to move the piston within the chamber and extend or retract the rod. Fluid is delivered and removed from the fluid chamber using a fluid pump. Conventional fluid pumps used with linear actuators have several disadvantages. For example, conventional fluid pumps are relatively inefficient. Fluid removed from the fluid chamber on one side of the piston is returned to a fluid reservoir from which the fluid is drawn through the pump for distribution to the other side of the piston. In addition to the long fluid flow path and significant valve requirements to control fluid flow, the fluid pressure required to open valves directing fluid back to the reservoir increases pressure on the back side of the pump and increases the power required to start the pump. Conventional pumps are also relatively complex and require a large number of components to direct fluid flow within the pump thereby increasing the size of the pump and actuator. Finally, conventional fluid pumps and linear actuators must be oriented in certain ways due to the effects of gravity on fluid levels in the pump.
The inventor herein has recognized a need for a fluid pump for a linear actuator that will minimize and/or eliminate one or more of the above-identified deficiencies.